FIELD: physics.
SUBSTANCE: method of determining speed of a moving object involves passing a beam of coherent light through an optical mask, having a pattern of alternating non-transparent and transparent regions formed on it, as a result of which an image of alternating light and dark bands is projected in the direction of the light beam, making the moving object cross the projected image such that part of the light beam is reflected from the moving object in form of a series pulses, detecting the reflected light pulses and frequency of the pulses and calculating speed of the object as a function of the frequency of pulses and known spacing of the image bands.
EFFECT: invention widens the range of measured speed values.
15 cl, 3 dwg
